Following last year's triple disaster in Japan, the EU decided to take a critical look at its nuclear power production and re-assess the safety and security of all nuclear power plants in the EU. All 14 Member States that operate nuclear power plants (Belgium, Bulgaria, Czech Republic, Finland, France, Germany, Hungary, the Netherlands, Romania, Slovak Republic, Slovenia, Spain, Sweden, United Kingdom) and Lithuania, which is decommissioning its nuclear power producing units, agreed to participate in these voluntary stress tests.

The stress tests go beyond safety evaluations performed during normal licensing process and periodic reviews. They assess whether nuclear power plants can also cope with extreme unexpected events. The Fukushima accident showed us that two natural disasters can happen at the same time: the nuclear power plant could withstand the earthquake but could not cope with an up to 20 meter high tsunami wave which followed and cut off the power supply to the plant.

The safety and security of nuclear power plants is the responsibility of plant operators and Member States. Ensuring and continuously improving nuclear safety is nevertheless the utmost priority of the European Commission. The Commission is currently reviewing the EU legal framework and will make, if appropriate, new proposals later this year. When proposing improvements to EU legislation and new non-legislative actions, the Commission will take into account the lessons learned from the stress tests.

What is assessed by the nuclear stress tests?

The stress tests assess whether a nuclear power plant can withstand the effects of the following events:

2) Man-made failures and malevolent actions. These events may include airplane crashes, fires and explosions close to nuclear power plants, whether accidental or resulting from terrorist attacks.

What is the state of play of the stress tests?

At the moment, we are in phase three of the stress tests: multinational teams consisting of Nuclear safety experts from EU Member States, including those who do not operate nuclear power plants (e.g. from Austria, Denmark, Ireland, Luxembourg) are currently analysing the national reports and verifying open issues on-site when necessary. They are identifying key strengths and weaknesses and will present concrete recommendations for improvement on nuclear power plant level. The peer review process started in January 2012 and will be completed shortly.

This is the final phase of the stress tests which consists of three distinctive phases:

1) Self-assessments. By 15 August 2011 nuclear plant operators reported the results of their self-assessments to national regulatory authorities.

2) National reports. The national regulatory authorities had to compile final national reports and submit them to the European Commission by 31 December 2011.

3) Peer reviews. The aim of this stage is to provide a transparent, objective and comprehensive EU-wide assessment of the situation.

Which experts are members of these multinational teams? How does it work?

Since beginning of January 2012, the peer review members are examining all reports and written material on an individual basis, having also the opportunity to ask for additional information from the nuclear power plant operator via the national authority.

In the first part of the peer review process, topical review meetings (for initiating events, loss of safety functions, severe accident management) were conducted in February, involving nuclear safety experts from nuclear and non-nuclear EU Member States, Switzerland, Ukraine and the European Commission, as well as observers from other countries (Croatia, Japan, USA) and the IAEA.

As a second step, country review meetings will take place. There are six country teams consisting of six experts from national nuclear safety authorities and a representative of the European Commission.

The team members and the countries they are visiting are published on the ENSREG website:

The national authorities could decide, to which countries they would like to send their experts to. There was no single country which opposed to specific experts checking their nuclear power plants.

The European Commission's in-house science service, the Joint Research Centre (JRC), has provided the Secretariat to the stress tests and contributed to the elaboration of the stress tests modalities and peer review methodology. Building on its experience in nuclear safety, the JRC has centralised technical support on nuclear safety to the EC High Level Task Force. The JRC team is composed of 18 experts and mobilises the JRC requested expertise in all the subjects of the stress tests. It provides the secretariat for the planning and execution of the review process and takes part in the peer review missions to the participant countries. In September 2011, the Member States' Nuclear Safety Authorities participating in the stress tests agreed that the JRC would also be the "rapporteur" of the peer reviews.

How do you make sure that results are credible?

As national experts are checking the power plants in other countries, this will lead to objectivity and make results comparable. There will be no majority voting in the multinational team. If one expert has doubts about the opinion of the others, his remarks will be included in the final report. We are aiming for the highest transparency possible.

In every multinational team, there are experts from countries which have nuclear power and from countries which have not, as well as from the European Commission. This adds objectivity and credibility.

It is now a year after Fukushima. Why are there no results available yet?

The Commission presented some initial results of the stress tests in its Communication adopted on 24 November 2011. However, until the peer review process is finalised, any conclusions on overall stress test results for a particular Member State or a specific plant would be premature. While the tests are done in the fastest possible manner, it would be wrong to press for early results in exchange for thorough and in depth.

When will the final results of the stress tests be known?

The Commission will present its final report on the stress tests to the European Council in June 2012.

Will the Commission propose any concrete action?

In parallel, on the basis of initial findings, the European Commission is reviewing the EU nuclear safety legislation and working on ways for improvement.

In particular the Commission is considering:

Minimum technical safety requirements. Today different Member States apply different safety margins in nuclear power plants. EU-level technical criteria in the areas of siting, plant design, construction and operation could be set. For instance, the criteria could establish a minimum distance of the plant from the sea. These criteria should be a reference point when licensing or checking the operations of the plants.

Licensing and checks. National regulatory authorities are responsible for issuing licenses for new nuclear power plants and controlling the operation of the existing ones. To do this effectively they need to be completely independent. Their decisions and the reasoning behind them should be made available for the public.

Cross-border emergency response. A possible radiological emergency would not stop at national borders. Therefore cross-border emergency plans should be put in place. These plans should foresee the availability and sharing of healthcare and emergency response equipment, such as back-up generators in the event of loss of power in the plant.

Improving nuclear liability coverage. Different Member States apply different liability regimes. For example, some countries require unlimited liability in terms of compensation to victims while in others only limited amounts are available. Victim protection should not depend on the nationality of the victims, therefore measures are needed to improve victim compensation in the EU.

Are the results of the stress tests public?

Yes. All reports, including national reports and results of the peer reviews, are or will be available at www.ensreg.eu.

What will happen if a plant fails the tests?

In case a nuclear power plant fails the test and an upgrade is not technically or economically feasible, it should be shut down. Decisions on individual installations remain a national responsibility. However, the fact that the results of the stress tests will be public should ensure that all necessary steps will be taken to guarantee the utmost safety and security of all nuclear power plants in the EU.

What was the EU's action as regards the controls on food products imported from Japan?

On 25 March 2011, the Commission took emergency measures via a Regulation, providing that all feed and food originated in or consigned from 12 prefectures around the nuclear power plant from Fukushima in Japan have to be tested before export to the EU. These measures complement the extensive testing and controls carried out in Japan. Since then, the EU measures have been regularly amended in order to take account of developments and of the data collected. The measures provide a very high level of assurance as to the safety of food and feed placed on the EU market. About 2000 samples of feed and food from Japan were controlled in 2011 since the accident for the presence of radioactivity. Only two samples showed non-compliant results.

What relevant research is the European Commission funding?

The European Commission is funding research on the safety of nuclear fuel and fuel cycles, nuclear waste management and nuclear safeguards and security. It is also funding research into the effects and mitigation of natural disasters, including earthquakes and tsunamis. Research is being funded through a variety of means, including:

- Euratom research and training programmes under the 7th Framework Programme (FP7). Euratom research and training programmes have existed for more than fifty years, since the Treaty was adopted. Under the 2012 work programme, a total of €53 million is available for research and training in the area of "Nuclear fission, Safety and Radiation Protection". As far as concrete collaboration with Japanese researchers is concerned, five research topics in three different activities have been identified in 2012 work programme: Impact of the nuclear accident in Japan on Severe Accident Management; Consequences of combination of extreme external events on the safety of Nuclear Power Plants; Contribution to low-dose risk research in Europe; Update of emergency management and rehabilitation strategies and expertise in Europe; and Euratom Fission Training Schemes.

- The Joint Research Centre (JRC). The JRC has long standing collaboration with Japanese research organisations in the safety of nuclear fuel and fuel cycles, nuclear waste management and nuclear safeguards and security. Following the Fukushima accident, several Japanese delegations visited the JRC - during these visits, several potential areas for collaboration were identified. The JRC's broad nuclear fuel safety competences have been and will be used in support of the Fukushima-Daiichi post-accident analysis, remediation and decommissioning. In this context, re-evaluation of existing Severe Accident works are being reviewed in collaboration with EU national research organisations and new aspects identified.

The JRC has also developed technologies and systems to provide scientific and technical support to global security and crisis management. They allow the collection of information, quantification of risks and the dissemination of warnings to mitigate both weather-driven and man-made disasters. This helps to reduce the risks to populations from events such as earthquakes and tsunamis. For instance, the JRC's tsunami alert system is part of the EU-UN Global Disaster Alerts and Coordination System (GDACS: http://www.gdacs.org/).

- The European Research Council. The European Research Council (ERC) funds top-level frontier research by awarding grants to individual scientists and their teams in any field of research. It contributes to better understand the generation process for earthquakes and tsunamis by funding several projects in these areas. Fields of study include the mechanics of faults in earthquakes, a floating robot capable of detecting seismic waves, and the action and reaction of civil protection and the population during natural disasters.